Folding unit for forming an empty cardboard box; the folding unit has a mandrel, around which a blank is folded to form the empty cardboard box. The mandrel has at least two parts, which are mobile in respect to one another between an expanded configuration, in which the two parts are further from one another so as to confer a maximum size to the mandrel, and a contracted configuration, in which the two parts are closer to one another so as to confer a minimum size to the mandrel.

Folding unit for forming an empty cardboard box; the folding unit has a mandrel, around which a blank is folded to form the empty cardboard box. The mandrel has at least two parts, which are mobile in respect to one another between an expanded configuration, in which the two parts are further from one another so as to confer a maximum size to the mandrel, and a contracted configuration, in which the two parts are closer to one another so as to confer a minimum size to the mandrel.

A method and a machine for realizing containers, including at least steps of impressing a shape in relief on a sheet of deformable material, enveloping the sheet about itself and reciprocally joining lateral flaps thereof in order to form a tubular blank, and closing a bottom end of the tubular blank.

Apparatus (10) for automatically producing tubular elements (100) to make smoking articles and/or products for food use, comprising at least one forming unit (12) configured to form the tubular elements (100) starting from shaped flat sheets (101). The forming unit (12) comprises one or more forming devices (29) which are moved by movement means (30) along a work path (PL) closed in a loop, in order to form the tubular elements (100).